Boom extension means having more than three boom extension members for use with a truck crane

ABSTRACT

A boom construction comprises a tubular base member which is adapted to be mounted on a platform or a vehicle in a manner permitting it to be pivoted about a horizontal axis and to be swung about a vertical axis. Three separate additional boom members are telescoped within the base boom member and are movable relative to the base member and each other under the control of a plurality of fluid control cylinders which are mounted within the boom members. The first control cylinder is pivoted to the first inner one of the additional boom members preferably at the inner end thereof and it carries a piston having a piston rod which is pivoted at its inner end to the base boom member. A second fluid cylinder is pivoted to the second inner boom member and has a piston which is slidable therein with a piston rod which is pivoted at its inner end to a second boom member. Finally, a third inner boom member which is telescopic within the interior of all of the other boom member carries a third fluid cylinder having a third fluid piston slidable therein with a third connecting rod therefor which is connected at its inner end to the second innermost boom member. A feature of the construction is that the piston rods connected between the base member and the first boom member and the second boom member and the first boom member are provided with a double set of flow passages therethrough so that the fluid pressure which is directed into the first fluid cylinder on a pressure side thereof and which will cause expansion of the first boom member in respect to the base member will be directed through the other passage and into the pressure side of the second fluid cylinder to facilitate expansion of the second boom member in respect to the first boom member. The outermost fluid cylinder requires a piston rod with only one passage to complete the pressurization cycle for each of the fluid control cylinders and the expansion of all the boom members to an erected position simultaneously.

United States Patent [72] inventor Masatoshiflanada Takamathu, Japan [21] Appl. No. 654,484 [22] Filed .luly19,1967 [45] Patented July 6, 1971 [73] Assignee Kabushiki Kaisha Tadano Teltkosho Takamatsu, Japan [54] BOOM EXTENSION MEANS HAVING MORE THAN THREE BOOM EXTENSION MEMBERS FOR USE [56] References Cited UNITED STATES PATENTS 3,212,604 10/1965 Garnett 212/55 FOREIGN PATENTS 418,560 2/1967 Switzerland 137/17 Primary Examiner-Gerald M. Forlenza Assistant ExaminerRaymond B. Johnson Attorney-McClew and Toren ABSTRACT: A boom construction comprises a tubular base member which is adapted to be mounted on a platform or a vehicle in a manner permitting it to be pivoted about a horizontal axis and to be swung about a vertical axis. Three separate additional boom members are telescoped within the base boom member and are movable relative to the base member and each other under the control of a plurality of fluid control cylinders which are mounted within the boom members. The first control cylinder is pivoted to the first inner one of the additional boom members preferably at the inner end thereof and it carries a piston having a piston rod which is pivoted at its inner end to the base boom member. A second fluid cylinder is pivoted to the second inner boom member and has a piston which is slidable therein with a piston rod which is pivoted at its inner end to a second boom member. Finally, a third inner boom member which is telescopic within the interior of all of the other boom member carries a third fluid cylinder having a third fluid piston slidable therein with a third connecting rod therefor which is connected at its inner end to the second innermost boom member. A feature of the construction is that the piston rods connected between the base member and the first boom member and the second boom member and the first boom member are provided with a double set of flow passages therethrough so that the fluid pressure which is directed into the first fluid cylinder on a pressure side thereof and which will cause expansion of the first boom member in respect to the base member will be directed through the other passage and into the pressure side of the second fluid cylinder to facilitate expansion of the second boom member in respect to the first boom member. The outermost fluid cylinder requires a piston rod with only one passage to complete the pressurization cycle for each of the fluid control cylinders and the expansion of all the boom members to an erected position simultaneously.

PATENTEDJUL 6197i 3.591.016

SHKET 2 UF 2 10 i6 i9 212024 Q 1 N VENTOR.

Nnsn rosm HA NA DA arm/even BOOM EXTENSION MEANS HAVING MORE THAN THREE BOOM EXTENSION MEMBERS FOR USE WITH A TRUCK CRANE SUMMARY OF THE INVENTION This invention relates, in general, to the construction of booms and, in particular, to a new and useful boom having a plurality of telescopic boom portions, which are controlled by a plurality of fluid pistons and cylinders arranged therewithin which are connected together serially to provide for the uniform expansion of all of the boom elements at the same time.

ln the boom means for use with a truck crane having an extension structure, it is an essential requirement that the boom means can be contracted to the shortest length possible when the crane is being driven to a working location while it can be extended to its longest length during operation. ln other words, it is required that the maximum extension rate as well as the maximum lengths of respective boom members composing the boom means be arranged within the allowable length of the overhang of the crane, in order to increase the efficient length of the boom members.

ln satisfying the requirements mentioned hereinabove, some of the existing boom extension means have adapted boom extension means having more than three extension boom members which permit greater increases in the extension rate of the boom members, having the longer size in length of respective boom members composing the boom means, and being operated by means of hydraulic hoists instead of manual operation; however, we have often met with the inevitable problems which will be described hereinunder in showing one example of the existing boom extension means.

ln the existing boom extension means constructed so that extension and retraction operation is made by means of a double-acting multistate hydraulic hoist, high costs and heavier weight in the double-acting multistate hydraulic hoist are inevitable and present serious problems. In such cases, especially, in increasing both the length of the respective boom members composing the boom extension means and in the ex tension rate thereof, the size of the double-acting multistate hydraulic hoist must be inevitably increased, since considerable buckling strength is needed in such hoists supported at the starting end portions of a piston rod and a hydraulic cylinder, and in which resultant considerable increases in cost and weight of the hoist fail to provide usability of the boom means. Meanwhile, in the boom expansion means having a multiple of hydraulic hoists arranged separately among respective boom members forming the boom means, such problems as how to arrange the hydraulic hoists therein, and how to supply oil to the movable hydraulic hoists according to the extension movement of the respective boom members has remained unsettled.

An object of the present invention directed at solving the above-mentioned problems is to provide a boom extension means including more than three boom members for increas ing the extension rate which is efficiently applicable to the longer sized boom members.

Another object of the present invention is to provide a boom extension means comprising an extension boom member including an outer cylindrical base boom member including a cylindrical first expansion boom member and a cylindrical second expansion boom member secured slidingly in a telescopic manner into the inside wall of the base boom member; a principal hydraulic hoist arranged in a desired position between the extension boom member and another extension boom member slidingly connecting thereto; respective hydraulic hoists arranged between the first and the second extension boom members and the base boom member, each of which are slidingly interconnected; the respective hydraulic hoists comprising piston rods having one end portion pivoted to the starting end portion of the inside wall of the outer boom members, and hydraulic cylinders, having one end fitted with a piston rod and being pivoted to the starting portions of the inside wall of the inner boom members; the hydraulic hoists, excluding the principal hydraulic hoist, including, respectively, two oil channels formed in each of piston rods therein; and the oil channels each having one end adjacent the piston forming openings to the cylinder chambers spaced on both sides of the respective pistons and having another end forming openings to the end portions of piston rods, so that oil pressure can be passed through the channels, whereby the hydraulic hoists can be operated.

In the accompanying drawings a preferred embodiment of a boom extension means according to the present invention is shown comprising four boom members:

P16. 1 shows a side elevation view of a truck crane body;

HO. 2 is a longitudinal sectional view of the main part of the truck body shown partially in section;

FIG. 3 shows a magnified longitudinal section view taken along lll-lll in FlG. 3; and

FIG. 4 shows a longitudinal section view of a hydraulic hoist shown partially in section.

Numeral 1 indicates a turning bed mounted on a chassis 2 of a truck body, and A indicates an expansion or extension boom member having a base boom member 3 pivoted at its end portion 4 to the upper end portion of the bed 1 and afforded up and down motion by means of a hoist 3 pivoted therein. The base boom member 3 forms an outer cylinder, into which the first extension boom member 6, the second extension boom member 7 and the third extension boom member 8 are secured, and each of the extension boom members 6, 7, 8 is slidingly extendible in a telescopic manner the structure of which is revealed hereinunder.

Numeral 9 indicates a hydraulic hoist being arranged in between the base boom member 3 and the first extension boom member 6 and comprises a piston rod 90, the end portion of which is secured at 10 about the starting end portion of the inside wall of the base boom member 3, and a cylinder 9b one end of which is penetrated by a piston rod and is attached at 11 about the starting end portion of the inside wall of the first extension boom member 6. Numeral 12 is a hydraulic hoist arranged between the first extension boom member 6 and the second extension boom member 7 and comprising a piston rod 12a of which end portion is attached at 13 about the starting end portion of the inside wall of the first extension boom member 6 and a cylinder 12a in the end portion of which is inserted a piston rod secured at 14 about the inside wall of the second extension boom member 7. 15 indicates a hydraulic hoist arranged between the second extension boom member 7 and the third extension boom member 8, and comprising a cylinder 15b whose end portion is attached at 16 to the inside wall of the second extension boom member 7 and a piston rod 15a whose end portion is secured at 17 to a desired portion of the inside wall of the third extension boom member 8.

Respective hydraulic hoists 9, 12, excluding the hydraulic hoist 15, include oil channels whose feeding system will be described later, so that oil can be passed through the hydraulic hoists 9, 12 in the direction of the hydraulic hoist 15 for supplying it to respective hydraulic hoists 12, 15.

Respective hydraulic hoists 9, 12, excluding the hydraulic hoist 15, have double pipe structures and two oil channels are formed inside of each hoist 9, 12. One end of the oil channel 18 is communicated by an opening 22 adjacent to the piston 20, with an oilchamber 21 spaced on that side of the piston rod, and one end of the oil channel 19 projects through the piston 20 and opens into an oil chamber 21 located on the other side of the piston rod. On the other hand, the other ends of the channels 18, 19 form openings at the end of a piston rod 9a.

Operating oil flowing into the openings at the end of the piston rod 9a can be fed through the two oil channels inside the piston rod 9:: into the oil chambers 21, 23 of the hydraulic hoist 9, and the oil supplied to the oil chambers 21, 23

operates the piston 20 and then, is supplied through oil channels 27, 28 to the hydraulic hoist 12 (not shown in the drawing) having a similar structure to that of the hydraulic hoist 9 and supplying operating oil fed therein to the hydraulic hoist 15 The boom expansion means is constructed, as described hereinabove, so that operating oil fed to the opening 26 is supplied through the oil channel 19 to the oil chamber 23 of the hydraulic hoist 9, whereby the hydraulic hoist 9 is expanded or extended. Operating oil supplied into the oil chamber 23 is also supplied through the corresponding oil channel 28 to the oil chamber located in the hydraulic hoist 12, from which operating oil is supplied to the corresponding oil chamber of the hydraulic hoist 15 through the oil channel, so that the hydraulic hoists l2, 15 are extended in the same way as the hydraulic hoist 9. In further description of the boom expansion means, operating oil supplied to the oil feeding opening 28 operates to extend the extension boom members 6, 7, 8, which causes extension of the main boom member A, while operating oil supplied to the hydraulic hoist 9 through the oil feeding opening 25 operates to retract and house hydraulic hoists 9, l2, 15 in place according to the retraction of the piston rods since operating oil is supplied to the oil chambers located on both sides of the pistons to the hydraulic hoists 9, l2, l5.

lclaim:

l. A boom construction comprising a truck chassis, a turning bed mounted on said truck chassis for rotation through a horizontal plane, an extendible-retractible boom pivotally connected on said turning bed, means for raising and lowering said boom in a vertical plane about is pivoted connection to said turning bed, said boom comprising a stationary tubular base boom member attached to said turning bed and said means for raising and lowering said boom being secured to said base boom member, a plurality of concentrically arranged tubular boom members being disposed within said base boom member and being displaceable between a fully retracted position at least partially within said base boom member and a fully extended position with said boom members projecting in a series arrangement outwardly from said base boom member for providing a selected length of said boom, said concentrically arranged boom members comprising at least a first boom member, a second boom member and a third boom member, in the fully retracted position said third boom member being positioned within said second boom member said second boom member being positioned within said first boom member and said first boom member being positioned within said base boom member, in the retracted position the inner ends of said first, second and third boom members closer to said turning bed being spaced outwardly from the end of said base boom member secured to said turning bed with the end of said second base member being spaced outwardly from the end of said first base member and the end of said third base member being spaced outwardly from the end of said second base member, a first hydraulic hoist is positioned between said base boom member and said second boom member and comprises an axially extending cylinder, a piston axially movable within said cylinder, and a piston rod secured to said piston and extending outwardly from said cylinder having an outer end spaced axially outwardly from said cylinder, the outer end of said piston rod being pin connected to said base boom member at a location between the inner end of said first boom member and the end of said base member secured to said turning bed and said cylinder connected at its inner end closer to said turning bed to the inner end of said first boom member, a

second hydraulic hoist is positioned between said first boom member arid said second boom member and comprises an axially extending cylinder'a piston axially movable within said cylinder and a piston rod secured to said piston and extending axially therefrom outwardly from said cylinder toward said turning bed, said piston rod of said second hydraulic hoist being pin connected at its inner end to the inner end of said first boom member at approximately the same transverse location as the connection of said cylinder of said first hydraulic hoist to said first boom member and the inner end of said cylinder of said second hydraulic hoist being connected to the inner end of said second boom member, a third hydraulic hoist being positioned between said second and third boom members and comprising an axially extending cylinder, a piston axially movable within said cylinder, and a piston rod secured to said piston and extending outwardly from the outer end of said cylinder, said piston rod being secured at its inner end within said cylinder of said third hydraulic hoist to said piston therein and extending outwardly and being secured at its outer end to said third boom member at a point spaced intermediate the ends of said third boom member, said cylinder of said third hydraulic hoist being secured to said second boom member adjacent the inner end of said second boom member so that said first and second boom members are displaced outwardly into their extended positions by the action of said cylinders of said first and second hydraulic hoists riding outwardly on said piston rods and said third boom member is displaced outwardly by the action of said piston rod of said third hydraulic hoist being displaced outwardly from the cylinder of said third hydraulic hoist secured at its inner end to said second boom member, said piston rods of said first and second hydraulic hoists having acentrally arranged axially extending passageway and an annular axially extending passageway disposed concentrically about said central passageway, said piston in each of said cylinders of said first and second hydraulic hoists dividing the interior of said cylinder into a pair of variable volume chambers as said piston is moved between the extended and retracted positions, said centrally arranged passageway extending through said piston rod and said piston into the chamber located in the outer end of said cylinder and said annular passageway terminating in said piston rod before it reaches said piston and having an opening therefrom into the chamber on the opposite side of said piston from the other said chamber so that said annular passageway is connected to the chamber located in the cylinder closer to the turning bed, said chamber closer to said turning bed in said first and second hydraulic hoists having an opening extending through the end of said cylinders connected to said first and second boom members, respectively, the walls of said cylinders of said first and second hydraulic hoists providing a passageway extending for the length of said cylinder from the outer end thereof to the end of said cylinders located closer to said turning bed, and the inner end of said cylinder of said first hydraulic hoist being positioned adjacent the inner end of said piston rod of said second hydraulic hoist and the inner end of said cylinder of said second hydraulic hoist being positioned adjacent the inner end of the cylinder of said third hydraulic hoist so that the flow of hydraulic fluid for displacing said first, second and third boom members between the extended and retracted positions passes between the respective first, second and third hydraulic hoists without additional crossover connections and the interconnecting flow of hydraulic fluid between adjacent said hydraulic hoists are located at the inner ends of said cylinders of said hydraulic hoists. 

1. A boom construction comprising a truck chassis, a turning bed mounted on said truck chassis for rotation through a horizontal plaNe, an extendible-retractible boom pivotally connected on said turning bed, means for raising and lowering said boom in a vertical plane about is pivoted connection to said turning bed, said boom comprising a stationary tubular base boom member attached to said turning bed and said means for raising and lowering said boom being secured to said base boom member, a plurality of concentrically arranged tubular boom members being disposed within said base boom member and being displaceable between a fully retracted position at least partially within said base boom member and a fully extended position with said boom members projecting in a series arrangement outwardly from said base boom member for providing a selected length of said boom, said concentrically arranged boom members comprising at least a first boom member, a second boom member and a third boom member, in the fully retracted position said third boom member being positioned within said second boom member said second boom member being positioned within said first boom member and said first boom member being positioned within said base boom member, in the retracted position the inner ends of said first, second and third boom members closer to said turning bed being spaced outwardly from the end of said base boom member secured to said turning bed with the end of said second base member being spaced outwardly from the end of said first base member and the end of said third base member being spaced outwardly from the end of said second base member, a first hydraulic hoist is positioned between said base boom member and said second boom member and comprises an axially extending cylinder, a piston axially movable within said cylinder, and a piston rod secured to said piston and extending outwardly from said cylinder having an outer end spaced axially outwardly from said cylinder, the outer end of said piston rod being pin connected to said base boom member at a location between the inner end of said first boom member and the end of said base member secured to said turning bed and said cylinder connected at its inner end closer to said turning bed to the inner end of said first boom member, a second hydraulic hoist is positioned between said first boom member and said second boom member and comprises an axially extending cylinder a piston axially movable within said cylinder and a piston rod secured to said piston and extending axially therefrom outwardly from said cylinder toward said turning bed, said piston rod of said second hydraulic hoist being pin connected at its inner end to the inner end of said first boom member at approximately the same transverse location as the connection of said cylinder of said first hydraulic hoist to said first boom member and the inner end of said cylinder of said second hydraulic hoist being connected to the inner end of said second boom member, a third hydraulic hoist being positioned between said second and third boom members and comprising an axially extending cylinder, a piston axially movable within said cylinder, and a piston rod secured to said piston and extending outwardly from the outer end of said cylinder, said piston rod being secured at its inner end within said cylinder of said third hydraulic hoist to said piston therein and extending outwardly and being secured at its outer end to said third boom member at a point spaced intermediate the ends of said third boom member, said cylinder of said third hydraulic hoist being secured to said second boom member adjacent the inner end of said second boom member so that said first and second boom members are displaced outwardly into their extended positions by the action of said cylinders of said first and second hydraulic hoists riding outwardly on said piston rods and said third boom member is displaced outwardly by the action of said piston rod of said third hydraulic hoist being displaced outwardly from the cylinder of said third hydraulic hoist secured at its inner end to said second boom member, said piston rods of said first and seCond hydraulic hoists having a centrally arranged axially extending passageway and an annular axially extending passageway disposed concentrically about said central passageway, said piston in each of said cylinders of said first and second hydraulic hoists dividing the interior of said cylinder into a pair of variable volume chambers as said piston is moved between the extended and retracted positions, said centrally arranged passageway extending through said piston rod and said piston into the chamber located in the outer end of said cylinder and said annular passageway terminating in said piston rod before it reaches said piston and having an opening therefrom into the chamber on the opposite side of said piston from the other said chamber so that said annular passageway is connected to the chamber located in the cylinder closer to the turning bed, said chamber closer to said turning bed in said first and second hydraulic hoists having an opening extending through the end of said cylinders connected to said first and second boom members, respectively, the walls of said cylinders of said first and second hydraulic hoists providing a passageway extending for the length of said cylinder from the outer end thereof to the end of said cylinders located closer to said turning bed, and the inner end of said cylinder of said first hydraulic hoist being positioned adjacent the inner end of said piston rod of said second hydraulic hoist and the inner end of said cylinder of said second hydraulic hoist being positioned adjacent the inner end of the cylinder of said third hydraulic hoist so that the flow of hydraulic fluid for displacing said first, second and third boom members between the extended and retracted positions passes between the respective first, second and third hydraulic hoists without additional crossover connections and the interconnecting flow of hydraulic fluid between adjacent said hydraulic hoists are located at the inner ends of said cylinders of said hydraulic hoists. 